An expert whose draft for Fiji's Constitution was scrapped by the interim government says he doubts interim Prime Minister Frank Bainimarama has read his government's replacement version.

In January, the Fijian government scrapped the draft constitution drawn up by an independent commission led by Professor Yash Ghai.

A replacement version was signed into law in September.

Professor Ghai has told Australia Network's Newsline program Commodore Bainimarama's comparisons between the commission's draft and the final product have been flawed.

"I think most dictators have a great capacity for self deception and he may be suffering from that," he said.

"I doubt if he has read the Constitution - he just repeats what his Attorney General tells him to say, and those are his words."

"He has made various statements about our Constitution which are inaccurate in his criticism [and] he has said many things in praise of their Constitution which are inaccurate."

The new document will replace the 1997 constitution that was set aside by the military regime four years ago.

It includes reforms to the electoral system, a clause on free speech and a Bill of Rights.

Professor Ghai says while parts of the final version borrow from his work, they are undermined by other alterations or omissions.

"For example, they have taken a fair bit from our Bill of Rights, but they have an over-arching sort of provision whereby it'd be very easy for Parliament to disregard a human right, whereas in our case there was an article dealing with limitations," he said.

"The whole scheme of a Bill of Rights can come to nought if they declare an emergency [and] there are no safeguards that we had built into the scheme for declaring an emergency.

"So now they have a carte blanche basically to, to de-supply or set aside the whole Bill of Rights."

Electoral system

Professor Ghai says he's also disappointed with the changes to the electoral system from the draft version.

Under the new system, individual regional constituencies have been abolished in favour of one national constituency - a change which the government says will force politicians to adopt a national focus.

Professor Ghai says the changes favour larger parties because they have to secure five per cent of the vote.

He says the use of an 'Open List' system - where the number of candidates elected for each party is based on the party's overall vote - also adds to the complexity.

"In an Open System...you can cross out the ordering of the party and change the order - which is a good thing, it gives people, the voters the power not to have to stick to the list drawn by the party," he said.

"Then they can add other names too - they can put somebody down there who is not even on the list.

"It means that the ballot paper could be very long, huge - I know that people in Fiji are used to quite complex electoral systems but this one is going to be very hard to cope with for most people."

Rights groups have raised concerns about the constitution's inclusion of a clause giving immunity to those behind the 2006 coup.

Professor Ghai says clauses on immunity were included in his draft because of pressure from the attorney-general and the prime minister.

He says the original version would have forced those seeking immunity to apologise.

"The immunity we gave, requires a prior oath by the people who seek its benefit to apologise for what they did, to say they would never, ever again do things like this, only then does the immunity come.

"Many, many people told us that: 'If they apologise, if they show that they are sorry and acknowledge that they have broken somebody's sacred rules, we will of course give them immunity'.

"But they wanted some recognition on the part of these people that they did something wrong and they would never, ever again do something like that."

Professor Ghai says there are also concerns with the difficulty in changing the constitution, and that several Decrees by the current government will remain in force after the elections.

He says he remains hopeful that Fiji may still be forced by pressure from the international community to adopt his version of the constitution.